Process for manufacture of incandescent bodies for electric lamps.



DNrrED s'rArEs ALEXANDER JUST AND FRANZ HANAMAN, or BUDAPEST, 'AUsTRIA- PATENT oErroE.

HUNGARY, ASSIGNORS To. EGYESULT IzzoLAMrA Es vILLAMossAeI REszvENY TARsAsAG, oFDJ-PEsT, AUSTRIA-HUNGARY.

PROCESS FOR MANUFACTURE OF lNC-ANDESCENT BODIES EOR ELECTRIC LAMPS.

Original application filed July 6,1905,8erial No- 268,523. vDivided and this application filed January 5,1907. Serial 110,360,924. n

Specification of Letters Patent.

Patented. May 29, 19071 To all whom it may concern:

Be it known that we, ALEXAN ER JUST, chemist, and FRANZ HANAMAN, chemical engineer, both subjects of the Emperor of Austria and residing at Budapest, Desewfiy .utcza- 3, in the Empire of Austria-Hungary, have jointly invented a certain new and useful Process for Manufacture of Incandescent Bodies for Electric Lamps, of which the following is a specification.

The present invention constitutes the first division of our a plication for U. S. Letters Patent for man acture of incandescent electric lamps, filed July 6, 1905, Serial Number 268,523, and has for its object the manufacture "of filaments of pure tungsten by means of a process which is based u on the substitution of the carbon containe in a filament by tungsten.

It has become known to convert carbon filaments into tungsten filaments by means of a process which consists in heating carbon filaments by means of an electric current in an atmosphere of oxychlorids of tungsten, in the presence of hydrogen, whereby the carbon of the filament becomes substituted by tungsten. Now, the experience has proved that if the said process 1s carried out in the describedway, viz. with use of a carbon filament, as a starting body, it is not possible to obtain pure tungsten bodies, because of the fact that the inner core of the carbon filament remains uninfiuenced by the reactions going on on the exterior only of the filament, or with other words, the reaction is not homogeneous throughout the whole section of the carbon .core, with the result that, while'the exterior (part of the core becomes entirely converte into tungsten, the inner part either undergoes alterations to a slight degree only or remains wholly unaltered. This fact constitutes a very important drawback, because in case of. subjecting such an imperfect body to an intense heat, such body becomes easily deteriorated. Overmore in order to obtain thereby such imperfect filaments, considerable time is required, the duration of which injuriously affects the economy of the manufacture. According to the present invention the said process is started with bodies conslsting of a mixture of tungsten and carbon,

or of a mixture of some tungsten compound tungsten filaments and secondly the .treatment.

ments are obtained, if from 2 to 10 g. tung- 0 or compounds and carbon, whereby firstly it 1 has become possible to obtain finally ure tion of manufacture is considerably decreased and the manufacture itself facilitated. In order to produce such filaments consisting of' a mixture of tungsten and car- 'bon, finely divided tungsten or some tungsten compound, which is readily reduced by car-. bon to a metal, such as tungsten ox1d tungstlc acid, tungsten sulfid or the like is mixed w th an or anic binding medium, such as solution of cel ulose in chlorid of zinc, collodion, coal tar, coal pitch or the like, the filaments being then formed by pressure in the usual manner, and thereupon (after a proceeding demtration'in case of applying collodion) these filaments are carbonized. As regards the quantity of the' tungsten compound employed in this mixture the proportlons should be determined in such a manner that in the finished filaments suflicient carbon is always present to impart the requisite 73,

strength to them, as it is thecarbonalone that im arts to such a filament the necessary strengtfi for withstanding the subsequent- Thus for example, efficient filastic acid are added to a-solution of 10 g. cellulose in 260 g. chlorid of'zinc of the specific weight 1.83, this mixture being then formed into filaments and carbonized in absence of air. The said filaments which conslst of car- 5 bon and tungsten in accordance with the present process are submitted to the followmg further treatment: The'filaments are su bmitted to an electric current in anatmosphere of vapor of the oxyhalogen compounds 9 of tungsten (such as tungsten oxychlorids) WO2Cl2,WOCl in the presence of a little free hydrogen. When the filament incandesces, the reactions indicated by'the following equations take place:

As willbe seen, in this reaction the carbon still contained in the filament is replaced by 100 tun sten.

at we claim as our invention and desire to secure by Letters Patent is: 1. The method of making incandescing ura- 55 bodies for electric lamps which consists in to be replaced totally by tungsten, substanproducing the said body from a mixture of tially as described carbon and tungsten and replacing the car- In testimony whereof we have signed our bon totally by tungsten, substantially as denames to this specification in the presence of r 5 5 scribed. I two subscribing witnesses.v

2. The method of maklng incandesclng V ALEXANDER JUST.

bodies for electric lamps Winch consists in heating a mixture of carbon and tungsten to a red heat in the vapor of oxyhalogen com- Witnesses: 10 pound of tungsten by an electric current in TOIBORS HAJOY,

the presence of hydrogen to cause the carbon CHARLES E. WALKER.

FRANZ HANAMA N. 

